Your electric RC airplane power system
You have your RC airplane but in order to push it forward through the air you need some kind of power system. On an electric RC plane, this power system consists of four parts:
- The battery
- The ESC, or speed controller
- The electric RC motor
- The propeller
As this is an RC airplanes for beginners article, let us take a brief look into each of the above parts that you need to make your electric RC airplane fly.
The battery is the fuel for your electric remote airplane and it is usually a LiPo battery. A LiPo battery is a Lithium Polymer battery widely used in the R/C hobby today. These batteries have commonly 1-6 cells adding about 3.7V each (actually, it is 4,2V/cell but 3,7V/cell is the nominal value). Therefore, a two cell LiPo is marked as 7.2V and a three cell LiPo as 11.1V and so on.
The good thing with a LiPo battery is that it does not have memory in the same way as e.g. a NiMh battery. You should also remember not to run the battery totally dead since that could ruin it.
The Electric Speed Controller, or ESC, will act upon your input on the throttle stick on your RC transmitter and feeds the rpm proportionally to the motor. Using a car as an analogy, this little gadget may be thought of as the carburetor. It controls the speed of your RC airplane.
You should always choose an ESC that can handle the max Amp of the motor that you are using and the current of the battery you intend to use.
The electric RC motor
All machines need a motor and the same goes for a RC airplane. The electric motors are either brushed motors or brushless motors, although the brushless are the ones that are mainly used today. They are commonly so called out runners, delivering a relatively high torque and can handle larger propellers without the need for a gear. The brushless motors also have a good weight to power ratio that makes them ideal in order to keep the weight of the RC airplane as low as possible.
When it comes to actually pull or push the plane forward through the air the propeller is the thing that handles the task. Different propellers have different characteristics and you can see that by the marking on them, e.g. 6×4 or 8×3. What these numbers show you is how the propeller will move the air.
If we take the 6×4 as an example the first number, in this case 6, show you the total diameter of the propeller from tip to tip. The second number, in this case 4, shows you the pitch and tells you that the propeller will pull or push your airplane forward 4 inches during one revolution.
In the case of a three bladed propeller, it would look 3x6x4, where the added 3 in the beginning show you the number of blades on the propeller. Everything else is the same as for a 2 bladed propeller.
How to select the correct power system combination for your RC airplane
It is very important that the combination of the listed parts above are correct with respect to each other and to the RC plane that they are going to pull or push forward through the air. Incorrectly combined you will end up with a burned ESC or a plane that will fly badly, if at all, since the power system cannot provide enough thrust.
So how do you choose the correct combination? There are ways to calculate your way toward the correct combo. This will not be covered here as that is for the more advanced users. A rule of thumb is always to select an ESC that can handle the max Amp of your motor and the current of the chosen battery.
The recommendation is though to choose a well-proven combination offered by your online RC shop or just ask at your local RC hobby shop.
- Electric RC World – good resource for the RC airplane beginner
- RCPowers Ultimate RC Course – review part 1